Treatment procedures are used in oil and gas production for a variety of purposes. For example, hydraulic fracturing is a form of stimulation treatment used to create conductive flow paths between the reservoir and the wellbore. Treatments which involve introducing a treatment fluid into the wellbore may be adversely effected by loss of the treatment fluid into highly permeable regions of the formation.
Several agents to prevent treatment fluid loss and/or divert treatment fluid have been developed. For example, U.S. Pat. No. 4,387,769 describes fluid loss control agents comprising a polyester polymer which is substantially insoluble in the wellbore fluid, but which degrades in the presence of water at an elevated temperature to oligomer which are at least partially soluble in a fluid present in the formation (e.g. oil and/or connate water dissolved in the subterranean hydrocarbon fluids). Polymers selected from the group of poly(D,L-lactide), cross-linked poly(D,L-lactide), and copolymers of glycolide and D,L-lactide are described as preferred.
U.S. Patent Application Publication US 2012/0285692 describes methods of treating a subterranean formation penetrated by a well bore by providing a treatment fluid comprising a blend including a first amount of particulates having a first average particle size between about 3 mm and 2 cm and a second amount of particulates having a second average size between about 1.6 and 20 times smaller than the first average particle size or a second amount of flakes having a second average size up to 10 times smaller than the first average particle size. The publication states that the particles(s) or flake(s) can be embodied as proppant.
U.S. Patent Application Publication US 2015/0041132 describes diversion of well treatment fluids from a high permeability zone to a low permeability zone within a fracture network by use of a mixture comprising a dissolvable diverter and a proppant.